The frame works of buildings and like structures most often involve trusses for the support of decks and in particular roofs that are pitched. The simplest example of a truss is the principal or main coupling of a roof, in which a horizontal tie beam is suspended in the middle by a king post to the apex of the angle formed by the meeting of two rafters, and with struts to prevent sagging of the rafters. The feet of the rafters are tied together by the beam and are thus incapable of yielding in the direction of their length, so that their apex becomes a fixed point to which the beam is tied. Despite this simplest form of truss, the space beneath the rafters is occupied by unsightly structural members necessary to establish the fixed apex of the rafters, the rafters being hingedly related at said apex and not tied together as a beam. With the present invention it is an object to provide an arched beam in place of the usual truss, eliminating the complexity of the usual truss beam, king post and struts, thereby freeing the space beneath the rafters.
Each rafter of a roof truss is a beam in itself, but limited in this respect by the hinged joinder at the apex of the roof. Therefore, the alignment of one rafter with the other, at opposite slopes of the truss, cannot be relied upon as a continuous beam. However, with the present invention, it is an object to provide a coupler that attaches rafters at their apex so as to establish beam continuity from one to the other.
The coupling of the present invention, as it will be later described, has as its object flat plates to be secured to the rafter beams by a multiplicity of fasteners in shear. A feature is the overlap of rafter ends at the apex of these angularly related beams, the complementary plates having flat interface engagement with the beam end surfaces for the penetration of said fasteners to transfer shear loads between the beams and plates.
A characteristic of rafter relationship is the symmetry of beam angularity at the apex, or the equivalent by the bisection of the apex as when the roof pitch is different at opposite sides. Therefore, it is an object of this invention to provide a symmetrical coupling comprised of identical members that are complementary and one applied to the other when engaged with overlapped rafter beam ends. With the present invention, the coupling member is fabricated of a rectangular sheet of material perforated to receive shear fasteners and formed to establish an angle with a bearing plate engaged with one beam end and a flange plate engaged with the other beam end and to establish a strap plate that extends from said flange plate to embrace the bearing plate of the complementary coupling member and the said other beam end engaged on said complementary bearing plate. The aforesaid relationship of plates is identically the same when considering either coupling member.
A general object of this invention is to provide simple and practical coupling hardware for continuing one angularly related beam member into another. With the present invention, the two identical complementary members are fabricated of flat sheet material sheared partially along one line from a point that determines the bearing plate angle formation and the line of joinder thereto of the strap plate, the first mentioned "one line" being angularly displaced from the last mentioned "line of joinder" as determined by the beam angularity and/or roof pitch.